Sub-surface connector for plural tubing elements



Sept. 12, 1967 P. S. BLOUDOFF UB-SURFACE CONNECTOR FQR PLURAL TUBINGELEMENTS Filed April 21. 1965 Ens m I ll???" l I v v 3 5 l h may I. ll YFiat?! ul 3 q P. a 6 R m y 7 O 7 8 3 3 .M m m T E w m m 255M 5 ,5. qmmmmmm m I 5 l R E T m E Y P B Y United States Patent 3,340,932SUB-SURFACE CONNECTOR FOR PLURAL TUBING ELEMENTS Peter S. Bloudotf,Whittier, Calif., assignor to Armco Steel Corporation, Middletown, Ohio,a corporation of Ohio Filed Apr. 21, 1965, Ser. No. 449,824 6 Claims.(Cl. 166-243) ABSTRACT OF THE DISCLOSURE This invention relates to asub-surface connector assembly for oil wells or the like in which aplurality of separate strings of tubing extend from the surface to adownwell pumping system.

There are many instances in which present practices relating to therecovery of oil dictate the use of a plurality of separate strings oftubing run side by side in the oil well casing. Pumping from dualproducing zones and pumping by hydraulically actuated downwell pumps arethe most frequent. Because in this instance one or more of the tubingstrings will convey fluid at very high pressure, the hydraulicallyactuated downwell pumping case is, perhaps, the most demanding.

At the present time, fluid actuated downwell pumps are frequently usedas free pumps; that is, the unit is seated in a prepared cavity at theproduction zone without any mechanical connection to the surface. Thecavity in which the pump is seated during operation comprises a numberof precisely located and related cylindrical elements having ports forthe introduction of power oil at high pressure, for the removal of spentpower oil, and for the removal of produced oil. The prepared cavity isadapted to receive a movable assembly of tubing and packing elementsthat are related to each other both radially and longitudinally in sucha manner that when seated in the cavity the necessary separateconnections to the several tubing strings are established. This assemblyis prepared at the surface and is lowered into the cavity. In thoseinstances where two or more separate strings of tubing extend from thesub-surface. assembly to the surface, it is advantageous and customaryto run a primary tubing into the well along with all of the elementsthat make up the lower cavity assembly and carrying a landing collar towhich these cavity elements are attached. After the primary tubing andthe cavity assembly are run and seated in the well, the separate sidestring or strings are run in and are connected to the landing collar inwhich a coupling is established between the cavity assembly elements andthe side strings. In many instances, attempts have been made to latchthe side strings in place in the landing collar, but these attempts havegiven mechanical trouble particularly when for some reason it becamenecessary to remove all for some of the tubing strings for the well.

Where it has been attempted to establish a hydraulic seal between theside strings and the conduits extending into the landing collar, it hasbeen found difiioult to lower the sealing elements into the well withoutdam- Patented Sept. 12, 1967 aging them to the extent that they wouldfail to function against the relatively high hydraulic pressures thatprevail. The damage has been due largely to the abrasive action of thecasing joints that the seals pass in their trip from the surface to thelanding collar.

The present invention has for its primary object to overcome thedisadvantages of the prior art and to provide a sub-surface connectorthat will enable the precise adjustment of the elements of a cavityassembly prior to its insertion into a well and will thereafter accept,locate, and seal the connectors carried by the subsequently lowered sidestrings.

Another object of the invention is to provide a sealing arrangement fora subsequently inserted side string in which only internal, and thusprotected, seals are used.

Other objects and advantages of the invention will become apparent fromthe following detailed description of a prefered embodiment thereof,reference being had to the accompanying drawings, in which:

FIG. 1 is a perspective view, with parts broken away, and parts insection, of a sub-surface assembly embodying the present invention;

FIG. 2 is a section on line 22 of FIG. 1;

FIG. 3 is a section on line 33 of FIG. 1; and

FIG. 4 is a central, vertical, sectional view of a protected sealelement.

Referring to the drawings and particularly to FIG. 1, the presentinvention is shown as a part of a sub-surface assembly in whichconnections and seals are made to three separate strings of tubing that,when installed, will extend from the cavity to the surface. The tubingstrings as shown comprise a primary string 10 and parallel side strings11 and 12. The primary string 10 may be of a diameter to accept astandard downwell pump, to be operated as a free pump.

The tubing strings 10, 11 and 12 may be considered as terminating in alanding collar 13. Below the landing collar there are conduits andconductors that correspond to the several tubing strings, but that forma part of a prepared cavity that cooperates with the stationary elementsof a movable assembly whether the stationary elements comprise parts ofa dual zone pumping system or parts of a fluid actuated downwell pumpingsystem. The primary tubing string 10 is threaded into the landing collar13 by straight threads, in a known manner, and a cavity extension tubingof corresponding diameter is inserted in the opposite side of the collaras is conventional. These threads are not shown in the drawing, sincethey are commonly used, although the cavity extension tube is designated10a in FIG. 1.

The landing collar 13 is also provided with side passages 15 and 16 thatare conically enlarged at the upper end to form respective guiderecesses or sockets 17 and 18. At the lower end the passages 15 and 16are threaded at 19, 19a to receive landing stern adapters 20 and 21.Since the assemblies associated with each of the passages 15 and 16 aresimilar, only one will be described in detail and the parts thereofshown in FIG. 2.

In addition to being threaded at its upper end for insertion into thelanding collar 13, the landing stern adapter is internally threaded atthe lower end to adjustably receive a landing stem 22.

The landing stem 22 comprises a tubular body adapted to receive aconductor pipe 24 at its lower end in a threaded or other joint 25. Dueto manufacturing tolerances, the length of the conductor pipe may varysomewhat so provision is made for longitudinal adjustment in theconnection of the landing stem to the adapter 20 and thus to the landingcollar 13. As above noted, the connection between the two. parts ispreferably made by threads on the adapter and a long series of threads26 on the landing stem 22. A lower locknut 27 is first placed over thethreads 26 and an upper locknut 28 is threaded over the upper portion ofthe same threads, and will bear against a shoulder 29 within the landingstem adapter when the parts are finally located in the properlongitudinal relationship. By using the opposing locknuts 27 and 28against the external and internal surfaces respectively of the landingstem adapter, adjustment of the landing stem will be preserved While theassembly is lowered into the well. A tack weld between the landing stem22 and the conductor pipe 24 can also be used to maintain the adjustedposition of the parts.

At its upper end the landing stem 22 is formed with a spear or pinextension 30 having a smooth exterior and a tapered upper extremity. Theultimate seal for the subsequently lowered side string is made againstthe exterior of the spear or pin extension 30.

The landing stem adapter 20 is provided with a peripheral series ofmilled slots 31 to assure the passage and expulsion of trash ordislodged foreign matter that may enter the space around the landingstem during the running of the side strings. The foreign matter is thusprevented from lodging against the sealing surface of the pin 30.

Each side tubing string 11 and 12 carries a similar seal and packingassembly at its lower end, so that it will be necessary to describe onlyone, as shownin FIG. 2.

A landing spear housing 33 is attached to the tubing string 11 by acoupling 34, and carries a friction ring 35 on its outer periphery justbelow the coupling. The friction ring 35 is preferably formed of brassor a metal having a similar modulus of elasticity and similaranti-galling characteristics. The landing spear housing 33 has an'enlargement in the inner diameter at 36 to receive a series of packingrings 37 that are held in place by a guide nose 38 threaded into thelower end of the housing 33. The packing rings 37 are preferably of thereverse chevron type for most effective sealing and are dimensioned fora close packing fit around the smooth exterior of the spear or pin 30.The internal diameter of the tubing string 11 and the landing spearhousing 33 is purposely made slightly larger than the bore of theconductor pipe 24 and the bore of the landing stem. In this way, highpressure Within the side string 11 will exert a hydraulic downward forceon the packing rings 37 tending to hold the spear firmly in place aroundthe pin 30. Thus the pressure within the tubing will not act in adirection tending to blow the tubing ofi? its seat in the landingcollar.

All of the parts below and attached to the landing collar 13 areassembled on the surface, with the proper longitudinal adjustment of theconductor pipes being made prior to tightening the upper and lowerlocknuts 27 and 28. When these parts are properly assembled, they arelowered into the well by attachment to the primary tubing until they areproperly located in the well casing.

When the parts are located in the casing of the Well, one of the sidestrings 11 or 12 is run in until the guide nose 38 enters the flaredsocket 17 in the landing collar 13. Inasmuch as there may be severalthousand feet of the small tubing made up at this time, it is notpossible for the operator at the surface to know which of the two ormore conical socket surfaces of the landing collar has been engaged bythe guide nose 38. He knows only that the parts have landed on thelanding collar. The operator next elevates the entire side string by afoot or eighteen inches and then makes up and runs the second sidestring, placing it properly in the right or left side of the casing asindicated in FIG. 3. There is not enough room in the casing for thesmall tubing strings to cross each other so that the second tubing isnecessarily run down the proper side of the well and the first tubing isforced to overlie its proper socket in the landing collar. The secondtubing string may be run and fully seated while the first string isstill elevated.

Seating of the tubing string comprises entry of the guide nose 38 overthe tapered upper end of the pin extension 30. This entry continuesuntil the guide nose seats against the lower end of the pin extension atwhich time the packing rings 37 will completely surround the pin orspear extension 30. The friction ring 35 engages the bore in the landingcollar at this time. It is possible to tell from the surface whether theparts are properly seated because the increased friction imparted by thering 35 will make elevation of the string somewhat more difficult thanthe similar raising of the previously lowered string which is stillelevated somewhat above the landing collar. It will be noted that thefriction ring 35 is not called upon to perform any sealing function butmerely to serve as an indicator to the operator at the surface that theparts are, in fact, in their desired location.

Once the second side string has been properly located and sealed, thepreviously elevated companion string may then be lowered fully intoplace, again using the friction ring 35 to indicate whether or not afull seating has been obtained. Since the mass of the ring 35, the areaof its contacting face, the coefficient of friction, and otherparameters are known, the configuration of a proper friction ring can becalculated to give a highly consistent interference fit between theseated parts.

It will be noted that the packing rings 37, upon which reliance isplaced to prevent loss of pressure of fluid in the side string, arefully protected by the guide nose 38 and by the housing 33 during theentire time that the assembly is being lowered into the well. Theseparts cannot become damaged by the abrasive action of the casing jointsthat they necessarily pass during their entry operation. Any foreignmatter that is dislodged by the guide nose 38 or the coupling 34 or bythe remainder of the tubing string that is run into the well will passout of the system through the milled slots 31 in the landing stemadapter and will not lodge in any position in which they may prevent theproper seating of the parts.

It will be seen that the present invention provides an arrangementwhereby certain of the parts may be conveniently assembled at thesurface with a precise adjustment and that thereafter the side stringsmay be run into the well and positively sealed with respect to thepreviously lowered movable well assembly element.

While the invention has been described in conjunction witha specificform and disposition of the parts, it should be understood that numerousmodifications and changes may be made without departing from the scopeof the appended claims. The disclosure has been made in conjunction witha primary tubing and two side strings, but it is equally adapted to oneor more side string assemblies as will be readily apparent.

What I claim is:

1. In a sub-surface connector having a plurality of tubing elementsextending downwardly therefrom when located in a well casing andconstructed and arranged to receive a plurality of tubing stringsextending from the surface, one of said tubing elements acting as aprimary tubing, a landing collar supported initially by said primarytubing, adapter means forming a separate and adjustable threadedconnection between said landing collar and at least one other of saiddownwardly extending tubular elements, said adjustable threadedconnection comprising upper and lower locknuts engaging a portion ofsaid adapter means, said landing collar having a downwardly taperingrecess overlying at least one of said tubing elements adapted to guideinto a predetermined location a subsequently lowered tubing string, andmeans carried within said recess to form a packing connection betweensaid subsequently lowered tubing string and one of said downwardlyextending tubing elements.

2. In a sub-surface connector having a plurality of tubing elementsextending downwardly therefrom when located in a well casing, theimprovement comprising a landing collar having separate threaded meansoperatively connected to each of said tubing elements, said threadedmeans including a landing stem having a packing pin extending into saidlanding collar, said landing collar having a downwardly tapering recessoverlying and surrounding said packing pin and adapted to guide asubsequently lowered tubing string into a predetermined position, andpacking members carried internally of said subsequently lowered tubingstring cooperating with the exterior of said packing pin to form a fluidtight connection therewith.

3. In a sub-surface connector having a plurality of tubing elementsextending downwardly therefrom when located in a well cavity, theimprovement comprising a landing collar having separate meansoperatively connected to each of said tubing elements, said meansincluding a landing stem having a packing pin extending into saidlanding collar, said landing collar having a downwardly tapering recessoverlying and surrounding said packing pin and adapted to guide asubsequently lowered tubing string into a predetermined position, andpacking members carried internally of said subsequently lowered tubingstring cooperating with the exterior of said packing pin to form a fluidtight connection therewith.

4. The improvement defined in claim 3 in which the effective internaldiameter of said subsequently lowered tubing string is large enough tocreate a hydraulic force tending to move said packing members over saidpacking pin in a sealing direction.

5. The improvement defined in claim 3 in which said subsequently loweredtubing string carries a friction ring engageable with a wall of saidlanding collar recess to resist displacement of said subsequentlylowered tubing string from its landed position in said landing collar.

6. In a sub-surface connector having a plurality of tubing elementsextending downwardly therefrom when located in a well casing, theimprovement comprising a landing collar, an adapter between said landingcollar and at least one of said tubing elements, a landing stem threadedinto, said adapter, said adapter having at least one peripheral recessfor the disposal of foreign matter from around said landing stern, saidlanding stern having a packing pin extending upwardly into said landingcollar recess, said landing collar having a downwardly tapering recessoverlying and surrounding said packing pin and adapted to guide asubsequently lowered tubing string into a predetermined position, andmeans carried within said recess to form a packing connection betweensaid subsequently lowered tubing string and the exterior of said packingpin.

References Cited UNITED STATES PATENTS 171,615 12/1875 Hardison 166-189X 2,488,931 11/1949 Penick 166-45 2,976,934 3/1961 Todee 1662432,999,544 9/1961 Conrad et a1 166134 3,083,768 4/1963 Althouse et a1.166189 X 3,098,524 7/1963 Brown 166-52 CHARLES E. OCONNELL, PrimaryExaminer.

I. A. CALVERT, Assistant Examiner.

3. IN A SUB-SURFACE CONNECTOR HAVING A PLURALITY OF TUBING ELEMENTSEXTENDING DOWNWARDLY THEREFROM WHEN LOCATED IN A WELL CAVITY, THEIMPROVEMENT COMPRISING A LANDING COLLAR HAVING SEPARATE MEANSOPERATIVELY CONNECTED TO EACH OF SAID TUBING ELEMENTS, SAID MEANSINCLUDING A LANDING STEM HAVING A PACKING PIN EXTENDING INTO SAIDLANDING COLLAR, SAID LANDING COLLAR HAIVNG A DOWNWARDLY TAPERING RECESSOVERLYING AND SURROUNDING SAID PACKING PIN AND ADAPTED TO GUIDE ASUBSEQUENTLY LOWERED TUBING STRING INTO A PREDETERMINED POSITION, ANDPACKING MEMBERS CARRIED INTERNALLY OF SAID SUBSEQUENTLY LOWERED TUBINGSTRING COOPERATING WITH THE EXTERIOR OF SAID PACKING PIN TO FORM A FLUIDTIGHT CONNECTION THEREWITH.